Burner structure and system



June 7, 1960 E. M. RULSEH BURNER STRUCTURE AND SYSTEM Filed April 1e, 1957 3 Sheets-Sheet 1 June 7, 1960 Filed April 16, 195'7 E, M. RULSEH BURNER STRUCTURE AND SYSTEM 3 Sheets-Sheet 2 INVENTOR.

June 7, 1960 E. M. RuLsr-:H

BURNER STRUCTURE AND SYSTEM Filed .April 1e, 1957 3 Sheets-Sheet 3 INVENTOR. I ETg/LISQ/z; BY KM, s

St-fes Pm y 2,939,521 lce Patented June 7, 1960 This invention relate-S te en burners" mining' fuel en and atomizing air, andparticularly topilot burners therefor also utilizing fuel oil and atornizing air.

This application is la continuation-impart of pending application Serial -No. 585,252, filedv May 16,

lt isfa generalobjectoflthe invention Yto provide a 1956, V,and now abandoned.

new and improved apparatus of the character described.,r i

' In oil burners'of relatively high capacities, ignition ofthe `main burner isrcommonly accomplished by rst establishing, by Vmeans, such as an electric circuit, a gas pilot fiiel'is ynot always available, however, and may even be prohibited in certain areas by local codes.` In such cases,

llame, which i'n turn ignites the main oil llames. Gaseous other means must be provided for ign-iting the main voil` flame.

While ignition of the main llame directly with an electric circuit is satis-factory vfor low fuel rates, since theV heat generated by the circuit is small and localized, it may not be sulicient to ignite the main ame when the oil burning rate is relatively' high. When the oil -ow rate is high, if the flame is not established almost immediately when flow starts, an unsafe condition exis-ts because a relatively large amount of foil can flow into the combustion-,chamber in only a few seconds, and in its highly atomized state can cause an explosion 'if ignited from lthe heatof the refractories. Thus, direct ignition by electric eir-- cuit is not always satisfactory. v

'Another method of ignition is `1by means of an oil pilot. In such arrangements, an electric circuit ignites a- Which in turn ignites themainvame, The low ow rateilow ow rate of atomized fuel oilin a separate nozzle' is easily ignited by the electric circuit and if for some reason ignition does' not occur, oil accumulates in only small quantities which do not create an unsafe condition, since the` rate of-ilowV is low and since controls may be provided to delay the mainoil iiowuntil the pilot is established.

Oil pilots of the. character described commonly employV a pressure atomizing nozzle,'that is, a nozzle .effective to atomize thev oil atthe pressure under which it is supplied to the nozzle.v fSuch nozzles have only a small orifice in the' tip -to limit ow, and often plug with carbon formed by unburned oil in the nozzle when subjectedrto high radiation temperaturesfrom the main liame and refractories. Further, a pressure atomizing nozzle requires relatively high pressure (in the nature of 100 p.s.i.) for satisfactory atomization, so that in furnaces utilizing low pressure oil and air under presure for/atomizing the oil at the inain'burner, a booster pump must be provided to establish the proper oil pressure at the pilot nozzle. booster pump may be obviated by providing a pilot which In such installation, the necessity fora 2 atomizing air to a pilot burner nozzle for lighting a main burner also utilizing :fuel oil and atomizing air.

VV,Another object is to provide a new and improved sysvteirl of the character described in the preceding paragraph wherein fuel oil may be supplied to the pilot burner from the 'oil llines supplying the main burner, and atomizing` air may be supplied to the pilot burner from the lines supplying air to the main burner.

yIn systems of the character described, the volumes and pressures of oil andlair required at the pilot burner are vsubstantially less than those desired at the main burner and must be regulated to obtain proper combustion atsthe pilot burner.

Accordingly, a further object is to provide a new and improved system of the character described, including ,means forregulating the ows of air and oil to the pilot Firetube boiler constructions conventionally include a`re tube which funotions'as a combustion chamber in which a mainburner nozzle is removably supported by 4means .independent of the -irejtube, and such mounting means may permit removal of the main burner from the rejtube for` inspection purposes withoutrthe necessity of opening the head of the boiler. However, these constructions have also included a pilotburner for the main burner mounted'` in the tire tube refractories in a manner that required opening the boiler head to provide access. to the pilot burner.' Such Aarrangements involved considerable time andlabor expense during shut down periods Afor inspection, maintenance and repair of theV pilot burner.

`With these considerations in mind, it is also an object of the invention to provide an integrated main burner nozzle .and pilot burner nozzle structure which is readily accessible .and removable as a unit for maintenance and repair.

Another object is to provide a new and improved burner structure of the' character described in the preceding paragraph wherein the main burner is separately retractable, leaving the pilot burner in position.

Other objects and advantages will become readily apparent from the following detailed description taken in connection vwith the accompanying drawings, in which: .Figured is a fragmentary, vertical, longitudinal sectional view illustrating V--aV boiler construction utilizing an integrated main and pilot burner structure embodying the principles of the present invention;

Figure 2 is a fragmentary elevational view of the boilerY construction and' integrated burner structure illustrated in Figure l, taken at about the line 2-2 of Figure l; 1 Y t Figure 3 is an elevational view of the burner structure illustrated in Figures 1 and 2, taken at about the linev 3`3 Vofliigure yl; t t Y Figure 4 is a diagrammatic illustration of a system embodying the principles of the present invention;

utilizes low pressure oil and air under pressure for lWith 'th' above and other 'considerations in mind, it is a morespecifcobject of the invention toprovide a new and improved system 'foisupplying fuel 'oil and Figure 5 is aV view'similar to Figure Il, illustrating aA modified integrated main and pilot Iburner structure,` wherein the main yburner is separately retractable;

Figure 6 is an elevational view, taken at about the line 6-6 of Figure 5; and

Figure 7 is an'elevation-al view, taken at about th line 7-7 of Figure 5.- t

While `illustr-ative embodiments of the invention are shown in the drawings and will be described in detailV herein, the invention is susceptible Yfor embodiment in many different forms, 4and it should be understood that l the present disclosure4 is to beconsidered as an exempliicationfof the principles of the invention and is not intended to limit the invention to the embodiment illusthe appended Iclaims.

Referring now to the drawings, Figures 1, 2 and 3 illustrate an integrated main burner and pilot burner mounting structure 10 embodying the principles of the present invention and adapted for use in the combustion chamberof atire' tubeboiler. As seen vixrFigure l; porev tions ofthe boiler areillustrated, 'including'aboiler" shell 11 which is conventionally provided with'a header plate (not shown) -for supportingthe end sloff'tubes forme ing multiple passes fory combustion ga'sesthroughx the; boiler. and 'for supporting afifretube= hvingan' end""por= tion 12 which projects beyond, the header plate-and;F to the end of the boiler shell 11; The end'portion *12" of" the fire tube is provided-internally with an-`annular ring 13Vof refractory material adjacent' the area of combustion in the fire tube. The end of -the boilershell'lfl closedby a doorstructure which` may be removably bolted on the end of the boiler shell or hingedly mountedthereon to permitvaecessintoltlieboiler shell;l As illustrated, the door structure for' closing-the end of'tlie* boiler shell includes iafclosure' plate 14 lined ir't'ternallyy with refractory material 15 adjacent the area-'off theefrev tube 12,' and a dish-shapedclosuremember'll'overlying the plate-14'.

The: plate 14; is formedawithvla' circular 1 opening- 17- adaptedlft'o receive the end portion vof vatubula'r burner housing member 18- which= receives the burnerfstructura and-forms with the `re-tube 12 a combustion'Y chamber 19.l Anannula-r, outwardly extendingange'ZI-on theA l tubularY burner housing 18 -abutsf against the closure-'g plate. 14 about-the opening 17'. The`dishj-sliapedVclosure member 16` isformed witlr ay circular opening`22f aligned lwith the'opening lfli--in the plate 14 andgadapted* to4 receive-thev end oi '=`a`-liollowl cylindrically shaped part" 23projectingoutwardlyffrom the member 16fand adapted? to be secured theretoby means such as bolts or screws (notshown.) passing-through amounting flange 24 and the member. 16.V The left-end'of the tubular burner- `housing 18 (as-'viewed in Figure l) is formed with anv outwardly extending-annular-ange `26 adaptedvto'be secured by means not illustrated to the cylindrical-part'rv 23. In`1use,the door member 16 may be removed from the pos-ition'illust-rated, taking -with itnthetubular burner'V housingrlS, after Vwhich the door member 14 may beY removed tot provideeaccessto the interior ofthe boiler shell, .all without the necessity of disinountingthe buf-ner structure; 10 from-.themembe'r -16.-'f

The door. members 14' and v16`-serve -to define Ian air plenumchamber. toY which ysecondary air may be supplied by means. notillustrated tosupport-A combustion` 'a1:"'th'e V burners. Secondary air passes lfrom the] air plenun chamber into the burnerwhousingmeitnber 18` throu'ghlplii" inlet openings 18! in .themember` 18.? 'e

'I'he integrated. main burnerk and-[pilot burner mountingstructure 10 includes a mounting platev26- adapted to be secured to the door of the boiler by means 'such as screws (not illustrated) passingthrough the'lhol'es 27 (Figure El),` through the flange-26 and into thev'holl'ow cylindrical projecting part 23. The mountingplate 26 supports a main. burner 28 and a .pilot burner 29 by means to be described presently.v Y

The maintv burner 28is1an integral structure formed of a clusterV of three. burner nozzles 30a-,30h land 430e- (.Figs. l and 2)' Fuel oil is supplied to the main burner 28 by meansoffa pipe.31',and:atomizing airis supplied to the main burner by an outer concentric air supply`A pipe 32. The main burner` 28Lis' supported bymeans of a threaded connection with the'air-supply` pipe'32'.v` The fuel` oil supply 'pipe'.x3l. is rigidly: supported fin th`e airv supply pipei32, and the two pipesfpass fthroughjthe4 centerrofV the` mountinglplate 26', with the air supply p'ipe* B12-being rigidly'secured tothe plate 2'6'by means*such*v as" 'a1-press,l t `of' the `pipe4 inthe rcentral ot'ieningl 333m the" plate.' Exteriorlyf l of "the Y combusti/en cli'am be; A the" l oilisupply. pipe 31-is providedwith` a fitting 35 ad`apted j for.A connection-with a suitablersource offfueloil, Sixniatasaal burner.

larly, exteriorly of the combustion chamber, the air Asupply pipe- 32 is provided with` a` fitting 36 adaptedto be connected with a suitable source of air under pressure. If desired, the fitting 36 may be supplied with a suitable gauge 37 `for indicating air pressure.

The pilot burner 29 includes a single burner nozzle 38 and is provided with a th readedly connected air supply pipe 39 rigidly connected--toand supporting the pilot T he ,burneralsosincludei a: fitting 140 VVconnected with a fual oil supply line `41. The pilot burner fuel supply-"line 41 is connected". through the medium of' a` reducer-42 toa fitting 43 describedmorefully hereinafter. 'I'heiit-ting- 43"is `collrlltlefl with'aball. check valve 44 which is in turn connected with a pipe length 45 threadedly mountedinandpassingthrough the mounting plate 26 and preferably provided, exteriorly of the combust-ion chamber, with a fitting 46 Iadapted to be connectedwith.a..suitable source of fueloil supplyA as explinedmore' fully' hereinafter; Air under pressure .for a'tom'zing the fuel oil at the pilot .burner 3 8' is supplied', acordingto the present invention, tothe pilot burner air in let; pipe 39"bymeans ofanair supply.1ine'48"connec'tedfwiththeV pipe' 39'through the medium of 'a reducer 49 andconnectedby means ofa fi-ttingo'with the air chamljeijinfthejmain burner 2Vaheadof` thepoint at which` air-' 1 and 'fuel' joil are. mixed as described more in detailpresently:

The' pilot burner'ZQis supported Abyemeans of amounting'braclcet"including anend p ortion 52 which is received' on. 'tlie" airjsupp1y pipej32 for themainuburnerz andlj retinedyinfpositionby means sucl'r as the set screw. illus.'-l tratedjat' l532 I'hepilot'burnermounting bracket'projectsA from thee air` supplypipe 32 and-'includesv an oppositer end portion54 which receives the pilot burner air. supply'pip'ei39 which maybe retainedV in position in the b rack'etlby means such as the set screw illustrated at 5'5. In this mannerth'e pilot burner isr supported integrally with the main burner and m'aybe adjustably positioned:

relative tothe main burner.

The burner structure illustrated includesV an.. electric ignition means 'for the pilot burner'comprised ofl a paix` ofi"'elfectrodesl 56l each including an insulating youter por-` tiony havingan electrically.' conductive sparking element i 571'passing'therethroughi The electrodes arelmountedon,

thepilot'burner mounting bracket in split' clamping portions 5? adapted to beclampediabout'the outer insulating portion' ofi tlie electrodes by means of cla'mpimz,y screws 60. i Each ofthe electrically conductive' sparking elements f. 57 includes al l'hook-shaped; conductive connector. 61" adapted't'o be'connectedwithra'coiled conductor 62.'. The coiledconductorsr 62v are connected respectivel'ywith-hookshapedfconnector ends 63 of conductive'posts 6.4' eachembedded in an-insulating sleeve 65; The. insulating sleeves. n

. 65a'refs'uitably'jfixed"in theV mounting` plate 26 andppass therethrough; and the posts-64'provide exposed terminals outside the combustion chamber for connecting thespark= ingeleinfents with a suitable sourceof power: By'looseningwtheiclamping bolts y60;' the position of the' electrodes 562may1be adjusted to properlyposition the sparking elementsi57 vrelative to the pilot burner ,nozzle 58, and theA coiledcond-uctors- 62 permit' such adjustment'while maintaining' aA circuit: Ther'nain burner'28 andthe'` pilotburner 29 are addi# ti'onallyVA supported in proper positions inv the combustion chamber by.' means off radially projecting .support rods lthreadedly mounted in the4 endportion 52 of the pilot Y burnermounting bracketA and engageabl'elwith the interior. wallff the" tubular burner housing '18'. i

It willfbe" appreciatedthat' the burnerl construction described above incorporatesfinto a single e structure a 1 main burner and"a pilot` burner". therefor; l'both' .burners being supportedby means ofthe mounting plate' 26",: andl therefore readily removable from the combustion chamber siinplyby'/ disrno'untingl the plate 261 Prior' art con- .e stijuetinn have cony'entionally'fmounted the pilot; burner-jv in portions of the boileror furnaceprop'er, such asl in the refractory 13 Vof the ret-ube 12, so that the pilot burner was not easily accessible for maintenance and repair, but required opening -up the Ifront head of the` boiler, i

such as by removal of the plates" 14 and 16 forming the door construction described. The arrangement' disclosed provides -for mounting of `the main burner and the pilot burner in a manner such that both are readily accessiblev to provide substantial savings in time and labor expenses' for maintenance and repair of theboiler. f

Referring now particularly to Figure 4, the integrated burner mounting structure described maybe utilized inl a system including `a fuel oil supply pump 70 having-its inlet connected by means of aline 71 vwith a suitable fuel supply tank, a portion off which is representedby the bracket 72 which mounts the line l71. Thefuel oil sup-` ply pump 70 has its outlet connected with a line 73 having a Ifuel oil strainer 74 vand leading to a lfuel oil meterng valve 76. 'When there is nor call -forV fuel at the burner, fuel oil is returned to the tank through a line 77 connected with the metering valve 76 and the tank'bracket 72.'

The line 77 includes a back pressure valve 78adapted to regulate the pressure of the fuel oil at `the valveV 76, such pressure being readableon a gauge 79 connected in the line 73. Y

Fuel oil is supplied from main burner 28 -by Vmeans of aline 80, a solenoid controlled shut off valve 81 and aline 82 suitably connectedlf with the fitting 35 (illustratedin Figure 1) `which communicates withrthe main burner 28.

Air'under pressure is supplied to the main burner 28 for atomizing the fuel oil by means of a compressor 83 which takes air in through an air cleaner 84, a manually controllable valve 85` andV a check valve 86. Air is pumped from the compressor 83 to an oil sump pit 87 which functions -as "an'air receiver and lubricating oil separator. Lubricating oilpasses tothe compressor 83 through a line 88 which includes a lubricating oil strainer 89. Atomiziug air passes yfrom the separator 87 through a line 90 to the fitting 36 (Figures land 2) which com-` municates with'the air supply pipe -32 leading to the mainburner 28. v

the metering valve 76 to the f pilot nozzle. v 'After the solenoid valve 93 is opened, the automatic" Accordingfto the present invention, the pilot burner 29 is supplied with fuel oil Ifrom the main burner fuel oil supply line 73 through a line 92 having a solenoid controlledshut off valve`93 suitably connected with the pipe section 4S (Figure l), the tting 43, and the line 41 which is connected with pilot burner 29. In order to obtain the proper oil volumes and pressures at the pilot nozzle,

the ow of oil to the pilot nozzle is controlled by means` which leads from the air chamber of the main burner 28.V

In order to obtain the proper air volumes and pressures at the pilot nozzle 38, the ow of airto the pilot nozzle is controlled bymeans ofthe air supply line 48. More spe# cically, the line 48 is one of predetermined cross sectional passage area and of Vpredetermined length'to provide the desied pressure drop atthe pilot nozzle. Y This represents an extremely simple arrangement for supply,

ing atomizing air to the pilot burner, and for controlling the flow of air in metered quantities to the nozzle to-obtain the desired mixture of fuel oil and atomizing air for eicient combustion.

In operation, the system illustrated may be controlled entirely automatically'if desired so'that when the boiler calls for heat, the fuel (pump`70 is immediately started, and oil circulates through the loop vincluding the lines 71, line 73, the strainer 74',the meterngvalve 76, line 77 ing Velements 57 to ignite the pilot ame.

pilot flame is ignited, lthe controls may be Veffective to' value is establishedagainsttliejsolenoid controlled valve 93: by means ofthe back pressure relief valve 78, and this pressure may be read on the gauge 79. In a system of the character illustrated, the pressure referred to may bev approximately 40 p.s'.i.

At the time the boiler calls lfor heat and the'pump 70 is started, the`compressor'8`3 may also be started, and air -is delivered through'the separator 87, theline 9|),vr the pipe A32, and tothe main burner ."58.V In the system 4'ill1'1strat"ed,` the pressure drop through' the main burner nozzle 30 may be about `l6 p.s.i., for example, and this u pressure may be read onthe gauge 37. At the same time,

air is supplied from the main burner 28 to the pilot burner 29 through; the airsu'pply line 48. Ignition and combustion'of the mixture of `airand atomized fuel oil at the l pilot burner 29 ismostleicient in a system of the char- 4acter described when the pressure vdrop through the pilot nozzle 38 vis about"`l0 p.s.i., for example. In order to fvobtain` the desired pressure drop at the pilot nozzle 38,' the'amount of air suppliedto the pilot nozzle is controlled by means of the supply line 48, as previously described.` Inthe system illustrated, the line 48 is coml.prised ofua tube ofi/a" outside diameter, with a .030"

wall "thickness and the length u may -be controlled to regulate thepressureldrop;

When `'the'b'oiler calls for heat, and the pump 70 and' compressor 83 are started,-the controlling monitor (not illustrated) mayvautomatically open the solenoid coni trolled valve 93 inthe Apilot burner-'fuel oil supply line.

Withair already being supplied at the pilot burner 29,' opening the valve Y93 provides a fuel oil supply to thel In order to obtain an ecient combustion at nozzleV 38.` the pilot nozzleA 38, thevtlow of fuel oil to this nozzle is controlled by lthe orice94; as previously described. In a system of the 'character described,the pressure drop in the oil flowat the nozzle 38 shouldV desirably be at about 10v p.s.i., for example. In the system illustrated, the

orifice 94 is Of-a predetermined size `such that for a pressure drop thereacross of about 30 p.s.i., for example,

a flow of fuel oil of about 2 g.p.h. is obtained at the controls may complete av circuit to the pilot burner-sparkcontinues to ow through the pilot nozzle so long as the main flame is burning, -and this functions to keep the` pilot nozzle cool `and clean so that it can not plug with carbon.

I When the boiler` no longercalls for heat, the valve 81 1s' closed, and the pump '70 and compressor 83 are stopped.

Supplying atomizing `alr'to the pilot burner nozzle from the main burner air ysupply lines through the use of a calibrated pressure drop tube avoids the need for additional valves, regulators andvv ttings and thus provides substantial economies. Y pilot burner from the main burner supply lines eliminates the necessity of a separate fuel oilsupply tank, additionalV pumps and ittings and also represents substantial economies. Y

While the burner structure andv system disclosed have been illustrated in connectionl with a re tubeboiler, it should be understood that the invention is by no means limited to fire tube boilers, but will have utility in other boilers and furnaces; the fire tube boiler has been chosen merely to illustrate one manner in which the :invention may be utilized.

Referring to Figures 5, 6 and 7, I have illustrated a" and back pressure .valve I78.-- Oilpressureof the desiredA 75. modified burner; mounting s'tructurelfor use .inacome When the When theriiame u Supplying fuel oil to vt-hev bustionchamber similar.:to;that illustrated :at ...19). in Fig: e urefl.` As -illustrated imiliigure 5,1.a;combustionchambere 19a .'isffformed in partebyeastubular (shaped .ihousinggnemr.C berg 18a.- havinginletopeningsi 18a'. forv admittingasecondary air, and an annular mounting flange 26a...

Thefrnodifiedburner; structure includesfga .mainlburner nozzle ellgandfa pilot burnerfnozzle.101hoth;supported.f bytmeans off-a ,mountingplate I103; v .'Ihe mounting plate.` is-adaptedtto be secnreclinppsition onthe mountngange: 2ta,- closing; one? end. offthe. combustion chamber,4 by: meanssof screws f, or", bolts (not. .illustrated) receivable in holes 104proyided inv theemountingfplateaand.- in..cooperat. ing-'openings not illustrated) Iin,thennounting.iial'ige 2611;.

In. this Tmoditicat ion,;` theman-butnen 100 and .the pilot. burner ltlsare removablewithftlie mounting Eplate ,aS;ran.. integral, unit, in.-.a-v manner.v similari to .-thatf illustratedr ,in Eg-y l. Also, the.modiiication,of Figure 5...provides.for retraction of, the.mainaburnerseparately, leaving the..pilotY burnerand zthemountinggplate .in position. Accordingly, a,supp ort for themainvburneriisprovided. in the. form of t a rigidy tubular part106 twhich passes-ithroughthemountf. ing. plate 1031A and is rigidly secured. therein Ain a suitablez manner. One end tportionr107.-f=tl1e tubular supportis.. positioned; so astotproject linto.. the .combustion,chamber.. 19a when the plate 103v is mountedand.,the opposite.- end portion.. 108..of the tubular.suppor t .proiectsfomthe opposite side.. of the..- mounting ,1 plate, exteriorly3f of. the. combustion, chamber. Y i Y Y As, in the. modification of Figure 1, .the .main-burner. nozzle is `supplied. with; fuel' oil; underr pressure. by means` of. asupply pipe 110,;and. is supplied with.atom= izmgair. under` pressure by means of anouter concentric.. supply.pipe.f111. The.. pipes iI and'lll .are.rigi:llyse.` cured together. in spaced. concentric;relationshipl and; at. the ends ,adjacent the'.V single main. burner nozzle 100,; ripgidly, support the, nozzle. The.. outer, air supplyi pipe.` 111` and. the. main...burner. ynozzle 100... are off.. an; outer: diameterwhich vpermits theseparts .to.be. telescoped with-A` in. the..tubular supporti-member.106,.and.the pipe 111.ix1. cludes a E-xed collar 112. adapted to,.slidably. engage. the.. Interior of the tubular support 106. Thus, the.Y main, burner. nozzle.and its.y supply pipes 1;10.'and. 111V are'` removably positioned in `the tubular. support. 106,.. and are removably-heldin. position by a,set.screw in. the end portion..1.08.of`the tubular support adapted to; engage theA outer pipelll.. n i

End portionspf `the.supply p ipes 110 and111 project.. exteriorl y of the mounting plate. beyondA thesend. 108 f ofi, thetubular. support, as.illustrated.inigure 5; The end of jthe, inner, ,oil supplyf pipe 110,.projects slightly beyond.- the endofthe. airv supply pipe-.111, 1and is provided with-v a .fi'tting1115, adaptedftofbe connectedwith a. suitablesource1of ..oill.under pressure, suchv asathe :oil supply pipe sz* iuustratedin Figure 4. The, end of the outwii.. centric. airrsupply pipe is providedwithithe tittin'g.- 116 adapted to,be. connected. with a..suitable source of air.v under pressure such as the air supply line 90 illustrated in ,lFigure 4. If desired,.-the itting..116; may. be, provided w1th` means fr connectnga.suitablepressure gauge. 117.

In order to support the -pilot burnerV nozzle 101, amounting .bracket 119 is. slidablyfitted on'thesexterior of"` tlie tubular support10v6, and may. be adjustably re@- tainedinposition by set.' screws such asthat illustratedat- 120 The mountingbracket119 isformed with; twozde.- pending ear portions;121,and 122 (Figuref) which are split for the purpose of releasably clamping suitable:` sparking,.;ignit'er elementsrwhich-fmay bei. retainedzin: adjustedjpositions byrneansgoficlamping screws-123; The split;- eari-.portionsfflZls and; 1221:.include'. depending.- leg' aniannular. -collari 126i for. supporting.; the 1. pilotv bui-nerfv nozzles-101:. Tlle;; pilotr burner zV nozzleemays be s retained in-adjusted positions in the collar 126 by:means':.of."a. clamping: screw. 127.;

oil linden. pressure. is suppliedto .thepilot burnery 'nozzle f throughfa ,titting 130 oni.the.side:.of,the nozzlefandaze; supply-,line..-131.e. Thef-pilotburner. fuel-:supply line.131i isconnectedthroughtheimediumpiaireducer 132 to.-a fit..w ting lrwhich' may 4inoludeanoriliceeforming means; similan-to, that-tillustrated .at' 43:and 94.f-in Figure. 1... Thef. fitting 133 iisfin-.Qturni connected Awithfaballx check.. valvev l'fliwhich; includes an, inletpassingghrough-.the mounting.; piateerigidly; securedin :the .latteri and terminating: in. ar iitting 135 adaptedeto-heconnectedfwith.a suitable source# of oilunderfpressureuch .as the fsupply-linea45 illustrated inaFignrez4.. i

. Sincetth'e maimburner1nozzlei100'in-the modification of. Eigurer 5;;isi separately. retractablef withoutY the. pilotburner;` the. pilot-.ainsupplyiline 'cannot -be connected with the; main burr-1er, supply f line. angin,Y the illustrationsIJ of# Figuresilfandtmf Insteadt,airtunderipressureis supplied, toiheipilot'burner n: zzlte;100.through` a reducer 137 which f isii connected yto .am inlet; line: 138 which passes through the.: mounting plate; ,is;.=rigidlysecured'y therein, and terminettes-a im a.;fittinge139.:adapted:toV be@ connected with aV suitableizsourcesofairzgunderpressure. Preferably, the ifting=139 should ,be connected..with.'the:main air supplyv line'z90fexteriorlyfofthefcombustion chamber at aposi:v tion near the elbow bend adjacent the litting36 in ,Fig-v. urez42;

As inztheomodi'cation0L-Figurer l-, the fuel snpplyf.v Iineanduthe:ar:snpply flinefor; thez-fpilot burner. 101-A- are formedztm.. or fincludemeansfto; ,receive-f fuel. and air un-- der pressure from themainburnersupply linesand. deliver. f thesentotthe .pilot burner ynozzle;at.reduced .pressuresand volumesfirelativeio.'thoseeat the mainburner.. Thus; the: principlesf of .operation'de'scribed :imconnection Vwith ,-Fig- -v uresil'-anddf also; apply fto thef-modiiicationof FigureSl In: a mannervv similar to thatdescribedyin connection. with theimodiiication of Figure 1; in Figure -5, the bracket, 119 isbadaptedto; releasablyzand adjustably support.electrica-l spark-ing; 'elements"r141 and.' 142. -which are A suitably-,k` encased i in insulating@ sleeves 143;- receivable; in: their split.` clampingiearszlZLand 122. The-.conductivesparkingI elements 141 and '142.eacli terminatefat the ends remote fromthe nozzle in hook-shaped connector portions 144.' C0led,., spring-like, extensible.: connectors 145 are. connected to the' end portions 144 and tofinsulated conductors.- 1.46.' which are-supported'in the mountingxplatell' extend. therethrough', and terminateyinrexteriorly positionedtaps 1'47' which' are 1 accessible for connectionzwith a.: suitable,- source of power;

Inaddition towthe mounting .bracket-.119, awsupportingr. bracket 149 is slidablyiitted on the tubular supportf106: andi may bey releasably retained' in adjustedpositions.v thereon by means of set screws150. The supporting. bracket-149 isrinithe form of aspiderfhavingfthree radial. ly ,extending legs 151i equally spaced: angularly about'. the bracket.v The legs' maybe provided,'.at;the. ends, with meansY to engage `the inner: surface ofV the tubular housing-18a, or thel ends of the legs may directly-engage: the-partlfa. A'szillustrated, the legs.Y 151 are :utilized Atof support a'diluser element`152which` is generally; dish-.f sh`aped,"h'aving. a cylindrical sidewall portion'153 and dif-'t fuser portionsl 154 :forgdirecting-` secondary airrtoward" the main burnerV nozzle 100.

Tlie dili'user'istattached to'the .legs 151 by fhaving arco-,'- ate*segmentsulSSboffthev cylindrical wall 153 slotted:.as,=

5 at:;156; deformed inwardly', out of round,; andsecured-:toi

the..legsr151 byfscrewsy157. The;cylindrica1-; sidewall.' 153 tits slidably in the.;tub.ularzhousingtflSa.

It `will.:bevunderstood that". the burner; structureffillusa trated in Figures 5, 6 and 7 may be connected:.in::a sysei. tem sucllpas ftliat :illustrated.iniiiigure' 4,' so that'zthe advantagesattrbutedto: the :'systcm' .of 1."ig ure.;4 also'applyxto; the ystructure of .:Figures.= 5'; v6 and .17; Themodicationof: the. latter iiiguresi.. in :addition-rto-:proyiding'z an rintegratedi maineliurner andzpilotz burnerzremovablezaas; a..funit';'.also' imaimanncn similar--tofrthatlillustratedfinrlignrea1;.. Trpcrniitsi.:separateerctraction: ofthe: rmaixrnburncrtz:

I claim:

1. vIn an oil burning system for a fire tube boiler or the like having a combustion chamber, in combination, a main burner oil atomizing nozzle for receiving fuel oil under pressure and oil atomizing air under pressure and passing the same in an atomized mixture to the combustion chamber, means providing a source of fuel oil at a predetermined constant pressure, a main burner fuel supply line connecting the source of fuel oil and the main burner nozzle to deliver oil to the nozzle at a predetermined pressure, means providing a source of atomizing air at a predetermined constant pressure, a main burner air supply line connecting the source of air and the main burner nozzle for delivering air to the nozzle at a predetermined pressure, a pilot burner oil atomizing nozzle adjacent the main burner nozzle for receiving fuel oil under pressure and oil atomizing air under pressure and passing the same in an atomized mixture to the combustion chamber to light the main burner, a pilot burner fuel supply line connecting the pilot burner nozzle and the source of fuel oil to supply fuel oil to the pilot burner nozzle, a xed ow restrictor and pressure reducer in the pilot burner fuel supply line for reducing the fuel pressure to a predetermined value at the pilot burner nozzle less than the oil pressure at the main burner nozzle, and a pilot burner air supply line connecting the pilot burner nozzle and the main burner air supply line to supply atomizing air to the pilot Iburner nozzle, said pilot burner air supply line having a predetermined cross-sectional passage area and a predetermined length providing a predetermined invariable capacity for reducing the air pressure to a predetermined value at the pilot burner nozzle less than the air pressure at the main burner nozzle.

2. In an oil burning system for a boiler or the like having a combustion chamber, in combinatiom, av main burner oil atomizing nozzle 'for receiving fuel oil under pressure and oil atomizing air under pressure and passing the same in an atomized mix-ture to the combustion chamber, means for supplying fuel oil to the main burner nozzle at a predetermined constant pressure, means providing a source of atomizing air at a predetermined constant pressure, a main burner air supply line connecting the source of air and the main burner nozzle for delivering air to the nozzle at a predetermined pressure, a pilot burner oil atomizing nozzle adjacent the main burner nozzle for receiving fuel oil under pressure and oil atomizing air under pressure and passing the same in an atomized state to the combustion chamber to light the main burner, means for supplying fuel oil to the pilot burner nozzle at a predetermined constant pressure less than the pressure of oil at the main burner nozzle, a pilot burner air supply line connecting the pilot burner nozzle and the main burner air supply line to supply atomizing -air to the pilot burner nozzle, and a iixed ow restrictor and pressure reducing mea-ns. in the pilot burner air supply line for reducing air pressure to a predetermined value at the pilot burner nozzle less than the pressure of air at the main burner nozzle.

3. In an oil burner system for a boiler or 'the like having a combustion chamber, in combination, a main burner oil atomizing nozzle for receiving fuel oil under pressure and oil atomizing air under pressure and passing the same in an atomized mixture to the combustion chamber, means providing a source of fuel oil at a predetermined constant pressure, a main burner fuel supply line connecting the source of fuel o-il and the main burner nozzle to deliver oil to the nozzle at a predetermined pressure, means for supplying atomizing air to the main burner nozzle at a predetermined constant pressure, a pilot burner oil atomizing nozzle adjacent the main burner nozzle for receiving fuel oil under pressure and an oil atomizing air under pressure and passing the same in an atomized mixture to the combustion chamber to light vthe main burner, a pilot burner fuel supply line connecting the pilot burner nozzle and the source of fuel oil to supply fuel oil to the pilot burner nozzle, a fixed ow restrictor and pressure reducer in the pilot burner `fuel supply line for reducing the fuel pressure to -a predetermined value at the pilot burner nozzle less than the oil pressure at the main burner nozzle, and means for supplying atomizing air to the pilot burner nozzle at a predetermined constant pressure less Ithan the air pressure at the main burner nozzle.

References Cited in the le of this patent UNITED STATES PATENTS 980,801 Kraus Ian. 3, 1911 2,311,404 Macchi Feb. 16, 1943 2,649,148 Tapp et al Aug. 18, 1953 

